High-field ESR measurements of CsCuCl3 under pressure

High-field ESR measurements of triangular antiferromagnet CsCuCl3 have been performed at 6 K under pressure using the pulsed magnetic field up to 16 T in the frequency region from 120 to 360 GHz. We found that both the phase transition field and the antiferromagnetic gap increased under pressure. The origin of the increase of the antiferromagnetic gap was concluded to be due to the increase of the easy-plane type anisotropy as well as the increase of the interchain interaction of this system. The increase of the easy-plane type anisotropy was consistent with the increase of the phase transition field under pressure as suggested by Nikuni and Shiba's theory. Author